Disclosed herein is a method for depositing multicomponent films each of which may be stoichiometric or non-stoichiometric such as, but not limited to, Germanium Tellurium (GeTe), Antimony Tellurium (SbTe), Antimony Germanium (SbGe), Germanium Antimony Tellurium (GST), Indium Antimony Tellurium (IST), Silver Indium Antimony Tellurium (AIST), Cadmium Telluride (CdTe), Cadmium Selenide (CdSe), Zinc Telluride (ZnTe), Zinc Selenide (ZnSe), Copper indium gallium selenide (CIGS). The method described herein may, in certain embodiments, be used to deposit the multicomponent films as an alternative to existing vapor phase deposition methods such as physical vapor deposition (PVD), chemical vapor deposition (CVD) or atomic layer deposition (ALD). Liquid-based precursor compositions or mixtures thereof for depositing the multicomponent film using the method described herein are also contemplated.
Certain alloys such Cadmium Telluride, Cadmium Selenide, and Copper indium gallium selenide (CIGS) are of industrial interest because they can be used as photovoltaic materials. Still other alloys including, but not limited to, GST (Germanium Antimony Tellurium alloy), IST (Indium Antimony Tellurium), and AIST (Silver Indium Antimony Tellurium), are used to fabricate electronic devices, including Phase Change Random Access Memory (PCRAM). Phase-change materials exist in a crystalline state or an amorphous state according to temperature. A phase-change material has a more ordered atomic arrangement and a lower electrical resistance in a crystalline state than in an amorphous state. A phase-change material can be reversibly transformed from the crystalline state to the amorphous state based on an operating temperature. Such characteristics, that is, reversible phase change and different resistances of different states, are applied to newly proposed electronic devices, a new type of nonvolatile memory devices, phase-change random access memory (PCRAM) devices. The electrical resistance of a PCRAM may vary based on a state (e.g., crystalline, amorphous, etc.) of a phase-change material included therein.
Among various types of phase-change materials used for memory devices, the most commonly used are ternary chalcogenides of Group 14 and Group 15 elements, such as Germanium Antimony Tellurium compounds of various compositions, including but not limited to Ge2Sb2Te5, commonly abbreviated as GST. The solid phases of GST can rapidly change from crystalline state to amorphous state or vise versa upon heating and cooling cycles. The amorphous GST has relatively higher electrical resistance while the crystalline GST has relatively lower electrical resistance.
One of the technical hurdles in designing a PCRAM cell is that in order to overcome the heat dissipation during the switching of GST materials from crystalline to amorphous states a high level of reset current has to be applied. This heat dissipation, however, can be greatly reduced by confining GST material into contact plugs, thus reducing the reset current needed for the action. The GST contact plugs are of high aspect ratio structure, and conventional sputtering process for GST film deposition can not achieve high conformality required. This drives the need for precursors and related manufacturing methods or processes for forming GST films which can produce films with high conformality and chemical composition uniformity.